fix(athena): report a failed query's error the way Athena does

StateChangeReason carried the raw engine call failure, HTTP envelope and all:
floci-duck execute returned HTTP 500: {"status":"error","message":...},
ending with the statement as the engine saw it, wrapped in COPY (...) TO. It is
now the engine's own message alone, such as Catalog Error: Table with name nope
does not exist!

src/main/java/io/github/hectorvent/floci/services/athena/AthenaService.java

@@ -59,6 +59,8 @@ public class AthenaService {
     public static final String DEFAULT_CATALOG = "AwsDataCatalog";
     private static final String DEFAULT_OUTPUT_BUCKET = "floci-athena-results";
     private static final String DEFAULT_WORKGROUP = "primary";
+    private static final Pattern ENGINE_FAILURE = Pattern.compile("^floci-duck \\w+ returned HTTP \\d+: (\\{.*})$", Pattern.DOTALL);
+    private static final com.fasterxml.jackson.databind.ObjectMapper FAILURE_READER = new com.fasterxml.jackson.databind.ObjectMapper();
     private static final Pattern TRAILING_SEMICOLONS = Pattern.compile("[\\s;]+$");
     private static final String DEFAULT_ENGINE_VERSION = "Athena engine version 3";
     private static final long MIN_BYTES_SCANNED_CUTOFF_PER_QUERY = 10_000_000L;
@@ -610,10 +612,35 @@ public class AthenaService {
 
     private void markFailed(String id, QueryExecution execution, Throwable failure) {
         execution.getStatus().setState(QueryExecutionState.FAILED);
-        execution.getStatus().setStateChangeReason(failure.getMessage());
+        execution.getStatus().setStateChangeReason(failureReason(failure.getMessage()));
         queryStore.put(id, execution);
     }
 
+    /**
+     * The engine's own explanation of a failed query, as Athena reports it: without the HTTP
+     * envelope of the engine call, and without the echoed statement, which shows the
+     * internal {@code COPY ... TO} wrapper rather than the query that was sent.
+     */
+    static String failureReason(String message) {
+        if (message == null) {
+            return null;
+        }
+        Matcher envelope = ENGINE_FAILURE.matcher(message);
+        if (!envelope.matches()) {
+            return message;
+        }
+        try {
+            String engineMessage = FAILURE_READER.readTree(envelope.group(1)).path("message").asText("");
+            if (engineMessage.isBlank()) {
+                return message;
+            }
+            int echo = engineMessage.indexOf("\n\nLINE ");
+            return (echo >= 0 ? engineMessage.substring(0, echo) : engineMessage).strip();
+        } catch (Exception e) {
+            return message;
+        }
+    }
+
     private record CreateDatabaseDdl(String name, boolean ifNotExists, String comment,
                                      String location, Map<String, String> properties) {
     }

src/test/java/io/github/hectorvent/floci/services/athena/AthenaQueryTextTest.java

@@ -0,0 +1,22 @@
+package io.github.hectorvent.floci.services.athena;
+
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+class AthenaQueryTextTest {
+
+    @Test
+    void dropsTheClosingSemicolonsAthenaAccepts() {
+        assertEquals("SELECT * FROM orders LIMIT 10", AthenaService.withoutTrailingSemicolons("SELECT * FROM orders LIMIT 10;"));
+        assertEquals("SELECT 1", AthenaService.withoutTrailingSemicolons("SELECT 1 ; ;\n"));
+        assertEquals("SELECT ';' AS s", AthenaService.withoutTrailingSemicolons("SELECT ';' AS s"));
+    }
+
+    @Test
+    void reportsTheEngineErrorWithoutItsEnvelopeOrTheWrappedStatement() {
+        String engine = "floci-duck execute returned HTTP 500: {\"status\":\"error\",\"message\":\"Catalog Error: Table with name nope does not exist!\\nDid you mean \\\"orders\\\"?\\n\\nLINE 1: COPY (SELECT * FROM nope) TO 's3://results/q.csv'\"}";
+        assertEquals("Catalog Error: Table with name nope does not exist!\nDid you mean \"orders\"?", AthenaService.failureReason(engine));
+        assertEquals("Failed to call floci-duck execute: timeout", AthenaService.failureReason("Failed to call floci-duck execute: timeout"));
+    }
+}

src/test/java/io/github/hectorvent/floci/services/athena/AthenaTrailingSemicolonTest.java

@@ -1,15 +0,0 @@
-package io.github.hectorvent.floci.services.athena;
-
-import org.junit.jupiter.api.Test;
-
-import static org.junit.jupiter.api.Assertions.assertEquals;
-
-class AthenaTrailingSemicolonTest {
-
-    @Test
-    void dropsTheClosingSemicolonsAthenaAccepts() {
-        assertEquals("SELECT * FROM orders LIMIT 10", AthenaService.withoutTrailingSemicolons("SELECT * FROM orders LIMIT 10;"));
-        assertEquals("SELECT 1", AthenaService.withoutTrailingSemicolons("SELECT 1 ; ;\n"));
-        assertEquals("SELECT ';' AS s", AthenaService.withoutTrailingSemicolons("SELECT ';' AS s"));
-    }
-}